Among catalytic converter devices disposed in an exhaust pipe to purify exhaust gas produced by an internal combustion engine, there is, as described in patent document 1, for example, a catalytic converter device where an electric current is passed through a metallic catalyst carrier that carries a catalyst to thereby raise its temperature such that a sufficient catalytic effect is obtained.
Incidentally, in the structure described in patent document 1, the metallic catalyst carrier is fitted in a shell (case), and a mat member having a buffering function is fitted and held between a conductive member of the metallic catalyst carrier and the shell. Here, it is assumed that water produced by the combustion of the internal combustion engine scatters as condensation water on the upstream side of the metallic catalyst carrier. The mat member is configured by an electrical insulating material, but when the shell and the metallic catalyst carrier end up being short-circuited by water droplets produced by scattered condensation water, sometimes the effect of heating the catalyst carrier drops because electricity also flows to the shell.    Patent Document 1: JP-A No. 5-253491